As long as the reallocation is legal they should be able to reallocate things no problem. I recently did a reallocation involving 3 different reservations and a points transfer. It was CRAZY! But the CM was super helpful. Some things to consider as far as legality of the reallocation:
1. If you used your 11 month window booking advantage, the points you reallocate to the reservation must also have that same booking advantage. For example, if you booked at 11 months at Beach Club you can only use Beach Club points in the reallocation. You would not be able to reallocate say AKV points to the 11 month out BC reservation.
Just give MS a call. They should very easily be able to tell you if you can or not. I've never had a problem and have done it twice now.